A costumed character wears a costume that usually (but not always) covers the performer's face. These range from theme park "walk-around" or "meetable" characters, the mascots of corporations, schools, or sports teams to novelty act performers. Some costumes cover the performer's face; others, especially those in theme parks, may leave the performer's face visible.

Costumed characters are intended to add to the fantasy experience by enabling visitors to encounter and interact with fictional characters, such as mascots for a company or organization. The characters are portrayed by employees in costume. Some of the costumes merely consist of clothing and makeup (e.g. Snow White, Sleeping Beauty, Batman), while those for non-human characters generally conceal the performer entirely and include a full-head/body mask (e.g. Donald Duck, Goofy, Bugs Bunny and his crew, Felix the Cat, Godzilla, Woody Woodpecker, and World Exposition characters such as Seymore D. Fair, Twipsy, and Haibao). A longstanding policy of Disney Parks is that the first category of characters, where the performer's face remains visible ("face" characters) are allowed to speak (usually on the basis of scripts carefully prepared in advance), while the second category of characters, where the face is covered ("fur" characters) are not allowed to speak and can only communicate through pantomime.[1]:343

An interesting phenomenon regularly seen at Disney Parks with costumed characters, especially "fur" characters, is that young children can become very scared at first sight, when they belatedly realize a character they may have seen only on television or in a book is much larger in person.[1]:342-343

For human characters based on a well-known media franchise that speak with visitors, theme park operators may prepare detailed scripts covering a variety of questions regularly asked by visitors, especially young children who have difficulty distinguishing between reality and fantasy. Performers cast in those roles are required to memorize and rehearse those scripts as part of their training, so they can learn their characters' backstories by heart and consistently respond in character to visitors.

At the largest theme parks (especially Disney Parks), popular costumed characters are often accompanied by one or more assistants in regular park uniforms, who handle customer service, security, and crowd control. This minimizes the necessity for performers to break character to deal with those kinds of issues. When a performer really needs a break (as staying in character is hard work), they simply give a prearranged signal, and their handler will then assure patrons the character will be back momentarily.

All theme park operators that present costumed characters enforce strict character performance regulations so that performers are never seen out of character by visitors. In the case of more elaborate costumes, they are never seen "with their head off." A related rule is that performers costumed as the same character (normally to allow the other to go on break) are supposed to avoid being seen side-by-side by the public.

In recent years, performers dressed as unauthorized versions of popular characters have appeared in popular tourist destinations such as Hollywood Boulevard and Times Square. They usually pose for photos and collect tips from tourists. Because they are not regulated or authorized, there have been many controversies and arrests involving them.[7][8]